Gate valve

ABSTRACT

In an embodiment, a gate valve includes a valve body including a first opening, a second opening, a flow passage from the first opening to the second opening, and a gate channel intersecting the flow passage. The gate channel is defined in part by two side walls facing parallel to a center axis of the flow passage, and wherein at least one of the side walls has a concave slot extending lengthwise along a center of the side wall. In an embodiment, gate for a gate valve includes a first disc-shaped side and a second disc-shaped side. The first disc-shaped side includes a first center guide and a first diameter, the first center guide being a convex ridge extending across the first diameter.

BACKGROUND OF THE INVENTION Field of the Invention

The invention pertains to the field of valves. More particularly, theinvention pertains to wedge gate valves.

Description of Related Art

Gate valves have been used for centuries in water supply systems tocontrol the flow of water or other fluids through pipes. For example,gate valves are often used in fire protection applications to close offwater mains. Referring to FIG. 1 and FIG. 2, one such wedge gate valve10 has a valve body 12 with a flow passage 13 between an inlet 14 and anoutlet 16, and first and second flanges 18, 19 at the inlet 14 and theoutlet 16. The flanges 18, 19 are used to bolt the gate valve 10 stablyto other water supply system components (not shown).

A gate 20 fits in a gate channel 22 inside the valve body 12. The gate20 can be moved into a closed position—fully into the flow passage 13from the gate channel 22—to block water flow between the inlet 14 andthe outlet 16. The gate 20 can also be moved into an openposition—withdrawn somewhat from the flow passage 13 into the gatechannel 22—such that water can flow through the valve body 12.

When the gate 20 is moved from the gate channel 22 to the closedposition, a rigid wedge portion 24 of the gate valve 20 mates with asealing surface 26 that extends semi-annularly from an end of the gatechannel 22 into a portion of the flow passage 13. The gate channel 22has a width to accommodate a width of the wedge portion 24 plus someadditional clearance. Toward the flow passage 13, the width of the gatechannel 22 narrows so that as the gate 20 moves to the closed position,the wedge portion 24 abuts and seals against the sealing surface 26. Theportion of the sealing surface 26 that extends into the flow passage 13is created by a recess or slot 28 into a perimeter surface 30 of theflow passage 13.

The recess 28 tapers into the perimeter surface 30 of the flow passage13. At a corresponding position on the perimeter of the gate 20, whichis to the gate channel side of a plane that is perpendicular to a centeraxis 32 of the gate channel 22 and that is parallel and intersectingwith a center axis 34 of the flow passage 13, the wedge portion 24abruptly or sharply transitions to a non-wedge portion 36. The non-wedgeportion 36 can have a constant width. A radially outward-facing surface38 of the non-wedge portion 36 abuts against the perimeter surface 30 ofthe flow passage 13 in the closed position to seal the flow passage 13.A width of the rigid wedge portion 24 drives a width of the gate channel22, which must be sized larger than the width of the non-wedge portion36 to accommodate the larger width of the wedge portion 24. In turn, thesize of the wedge portion 24 and the gate channel 22 affect the size ofother parts and the overall size and weight of the gate valve 10.Further, with the sharp transition from wedge portion 24 to non-wedgeportion 36, the parts must be manufactured with relatively tightdimensional tolerances in order to yield a reliable and consistent seal.

The gate 20 is connected to a stem 40 at a first end 42 of the stem 40,which is moved along the center axis 32 of the stem 40 to move the gate20 between the open and closed positions. The stem 40 can be partly orfully threaded. The gate 20 can be connected to the first end 42 by acollar or swivel 41, which is internally threaded to engage the threadedportion of the stem 40, allowing the stem 40 to rotate and drive thegate 20 linearly along the center axis 32 while the gate channel 22 andwings 44 engaging a corresponding channel (not shown) in the recess 28of the gate 20 prevent the gate 20 from rotating. In variousembodiments, rotation of the stem 40 can be driven manually orautomatically.

The stem 40 extends away from the flow passage 13 and the gate 20through the gate channel 22 to and through a valve cover 46, which ismounted on a third flange 48 at the gate channel 22. A seal 50 iscompressed between a flat surface of the valve cover 46 and the thirdflange 48. The size of the third flange 48, which adds additional weightitself to the wedge gate valve 10, is sized large enough to accommodatethe size of the gate channel 22 and wedge portion 24. Due to the sizeand weight of the wedge gate valve 10, four or more bolts 52 arerequired to secure the valve cover 46 to the flange 48.

A seal plate 54 is bolted to the valve cover 46 to cover and seal anopening 56 in the valve cover 46 over the stem 40. Bolts 58 are used tosecure the seal plate 54 and to compress a seal element 60 between theseal plate 54 and the valve cover 46 to facilitate making a fluid-tightseal there.

SUMMARY OF THE INVENTION

A wedge gate valve is disclosed herein that, compared to conventionalwedge gate valves, has a reduced size and weight, improved structuralstrength, and improved sealing functionality.

In an embodiment, a gate valve includes a valve body including a firstopening, a second opening, a flow passage from the first opening to thesecond opening, and a gate channel intersecting the flow passage. Thegate channel is defined in part by two side walls facing parallel to acenter axis of the flow passage, and wherein at least one of the sidewalls has a concave slot extending lengthwise along a center of the sidewall.

In an embodiment, gate for a gate valve includes a first disc-shapedside and a second disc-shaped side. The first disc-shaped side includesa first center guide and a first diameter, the first center guide beinga convex ridge extending across the first diameter.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows an exploded view of a gate valve according to aconventional embodiment.

FIG. 2 shows a partial section of a gate valve, with a transparent viewof a gate, and with sealing surfaces of the gate highlighted, accordingto the conventional embodiment of FIG. 1.

FIG. 3 shows a perspective view of a disassembled wedge gate valve,according to an embodiment.

FIG. 4A shows a valve cover and seal.

FIG. 4B shows a cross section of a portion of the valve cover and sealof FIG. 4A assembled on a ridge defining an opening of a gate channel.

FIG. 5 shows a disassembled wedge gate valve and disassembled gate,according to an embodiment.

FIG. 6 shows a front view of the wedge gate valve of FIG. 4A, with thewedge gate in a gate valve body.

FIG. 7 shows a cross sectional side view of the wedge gate valve of FIG.6.

FIG. 8 shows a cross sectional side view of the wedge gate valve of FIG.6.

FIG. 9 shows a cross sectional side view of the wedge gate valve of FIG.6.

FIG. 10 shows a cut away perspective view of the wedge gate valve ofFIG. 3, with a radially facing surface sealing against a perimetersurface of a flow passage, the sealing of the radially facing surfacehighlighted.

FIG. 11 shows a cut away perspective view of the wedge gate valve ofFIG. 3, with the gate wedged axially to form a seal between axiallyfacing surfaces of the gate and the gate valve body, the sealhighlighted.

FIG. 12 shows a cut away perspective view of the wedge gate valve ofFIG. 3, with the gate in a closed position, and the seal transitionbetween a radially facing surface of the gate and an axially facingsurface of the gate, the seal transition highlighted.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, reference is made to the accompanyingdrawings that form a part thereof, and in which is shown by way ofillustration specific example embodiments in which the present teachingsmay be practiced. These embodiments are described in sufficient detailto enable those skilled in the art to practice the present teachings andit is to be understood that other embodiments may be utilized and thatchanges may be made without departing from the scope of the presentteachings. The following description is, therefore, merely exemplary.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a”, “an”, and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on”, “engaged to”,“connected to” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto”, “directly connected to” or “directly coupled to” another element orlayer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”,“lower”, “above”, “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

Embodiments of a wedge gate valve are disclosed herein that utilize aflexible wedge gate design providing a reduced size and weight of thewedge gate valve, and an improved sealing function of the gate in aclosed position. FIG. 3 shows a perspective view of a disassembled wedgegate valve 100, according to an embodiment. Referring to FIG. 3, thewedge gate valve 100 has a valve body 102 with a flow passage 104between an inlet 106 and an outlet 108, and first and second flanges110, 112 at the inlet 106 and the outlet 108. The flanges 106, 108 areused to bolt the gate valve 100 to other water supply system components(not shown). Fluid can flow through the flow passage 104, which isdefined by a cylindrical, radially inward-facing perimeter surface 114.

Fluid flow through the flow passage 104 can be regulated by moving agate 120 between an open position and a closed position. In FIG. 3, thegate 120 is shown outside the valve body 102, but the gate 120 isconfigured to be inside the valve body 102 and moved in a gate channel122 between the open and closed positions. The gate channel 122intersects the flow passage 104. In the depicted embodiments, the gatechannel 122 and a center axis 124 of the gate channel 122 areperpendicular to the flow channel 104 and a center axis 126 of the flowchannel 104, but it is conceived that the flow channel 104 can intersectthe gate channel 122 at any angle. As discussed further herein below,the gate channel 122 has a smaller width and weight than conventionalwedge gate valves.

In the closed position, the gate 120 is positioned as far as it will gointo the flow passage 104, to seal off the flow passage 104. In theclosed position, some of the gate 120 can also still extend out of theflow passage 104 into the gate channel 122. In an open position, thegate 120 is moved toward the gate channel 122, away from the closedposition, or in other words, withdrawn somewhat from the flow passage104 into the gate channel 122, enough to eliminate the sealing of theflow passage 104 and allow fluid to flow through the flow passage 104.In a fully open position, the gate 120 is moved as far as it will gointo the gate channel 122 and out of the flow passage 104, or entirelyout of the flow passage 104.

To move the gate 120 between the fully open position and the closedposition, the gate 120 can be connected to a stem 130, such thatrotation of the stem 130 moves the gate 120. When the gate 120 is in thevalve body 102, the stem 130 can extend from the gate 120 through thegate channel 122, and through an opening 132 of the gate channel 122 atan end of the gate channel 122 opposite the intersection of the gatechannel 122 with the flow passage 104. In the depicted embodiment, thestem 130 has a threaded portion 134 configured to engage a threadedportion 135 of the gate 120, such that as a result of rotation of thestem 130, the gate channel 122 prevents the gate 120 from rotating withthe stem 130, and the gate 120 is threaded linearly along the threadedportion 134.

To facilitate the smooth movement of the gate 120 in the gate channel122, the gate 120 can have a center guide 136, which is a convex ridgeextending across a first side 138 of the gate 120 along a diameter D1 ofthe gate 120. The center guide 136 can be congruent with a concave slot140 extending along a center of a first side wall 142 of the gatechannel 122. A second side 144 of the gate 120 opposite the first side138 can also have a center guide, and a second side wall 146 of the gatechannel 122 opposite the first side wall 142 can also have a concaveslot. The gate channel 122 is also defined by a third side wall 148 anda fourth side wall 149 opposite the third side wall 148. The third andfourth side walls 148, 149 are between the first and second sidewalls142, 146. The distance between the first and second side walls 142, 146(i.e., across the third and fourth sidewalls 148, 149) defines a widthW1 of the gate channel 122, which is shorter than the distance betweenthe third and fourth side walls 148, 149 (i.e., across the first andsecond side walls 142, 146). The convex ridge(s) and the concave slot(s)can have uniform curvature across their respective lengths to facilitatesliding of the convex ridge(s) within or against the concave slot(s).

With the center guide 136 and concave slot 140, side rails or wingsextending from a circumferential side 151 of the gate 120 areunnecessary. The circumferential side 151 defines a circumference C, afirst circumferential endpoint CE1, a second circumferential endpointCE2, and two circumferential midpoints CM1, CM2, the firstcircumferential endpoint CE1 being at an intersection of the diameter D1and the circumference C, the second circumferential endpoint CE2 beingat an intersection of the diameter D1 and the circumference C, the firstand second circumferential midpoints CM1, CM2 each being half waybetween the first and second circumferential endpoints, thecircumferential side extending in a continuous curve through thecircumferential midpoints CM1, CM2. The circumferential side 151 definesthe radially outermost surface of the gate 120 at the first and secondcircumferential midpoints CM1, CM2. In other words, no rails or wingsprotruding from the circumferential side 151 of the gate 120 arenecessary.

The opening 132 of the gate channel 122 can be covered with a valvecover 150. The valve cover 150 is shaped and sized to fit and mate witha ridge 152 defining the opening 132. A seal 154 can also be sized andshaped to fit on the ridge 152, and to be sandwiched between the ridge152 and the valve cover 150. FIG. 4A shows a semi-transparentperspective view of the valve cover 150 revealing the seal 154 installedon the valve cover 150, and FIG. 4B shows a cross section of a portionof the valve cover 150 and the seal 154 of FIG. 4A assembled on theridge 152. Referring to FIGS. 3, 4A, and 4B, the ridge 152 exists inmultiple planes. A first section 302 of the ridge 152 and a secondsection 304 discontinuous with the first section 302 each extend in afirst plane. A third section 308 extends in a second plane angled towardthe axis 126 from the first plane. The third section 308 connects thefirst section 302 and the second section 304. Similarly, a fourthsection 312 extends in a third plane also angled toward the axis 126.The fourth section 312 also connects the first section 302 and thesecond section 304. Along each of the sections 302, 304, 308, 312, asseen in FIG. 4B, the ridge 152 includes a lip 316, defining a sealchannel 318 around the perimeter of the ridge 152.

The valve cover 150 has a corresponding shape, with a first matingsurface 320 to mate with the ridge 152 along the first section 302, thesecond section 304, the third section 308, and the fourth section 312.The valve cover 150 has a first section 322 configured to cover thefirst section 302 and the second section 304 of the ridge 352, a secondsection 324 angled similar to the third section 308 of the ridge 152 tocover the third section 308 of the ridge 152, and a third section 326angled similar to the fourth section 312 of the ridge 152 to cover thefourth section 312 of the ridge 152. The valve cover 150 also has aclamping extension 328 extending at an angle from parallel with thefirst mating surface 320. The clamping section 328 is on two opposingsides of the first section 322, the second section 324, and the thirdsection 326 of the valve cover 150, such that pressing the valve cover150 onto the ridge 152 creates force components on the lip 316 and theseal 154 perpendicular to the axis 124 of the gate channel 22, inaddition to the force component acting parallel to the axis 124 of thegate channel 22. Configure the angle to be 45 degrees yields equal forcecomponents, though the angle can be any desirable number of degrees. Atan end 330 of the second section 324 of the valve cover 150, and at anend 332 of the third section 326 of the valve cover 150, the clampingsection 328 can be omitted, and a force component acting perpendicularto the axis 124 of the gate channel 22 can still be achieved because thesecond section 324 and the third section 326 are at an anglenon-perpendicular with the axis 124 of the gate channel 22. The secondand third sections 324, 326 can match the angle of the clamping section328 with respect to the first mating surface 320. Securing the valvecover 150 with force components in directions parallel and perpendicularto the axis 124 of the gate channel 22 decreases the quantity of boltsnecessary to secure the valve cover 150, facilitating improvedstructural strength, a better seal, and easier assembly/disassembly.

Referring again to FIG. 3, on the third side wall 148 of the gatechannel 122 and the fourth side wall 149 opposite the third side wall148 are a first bolt flange 160 and a second bolt flange 162. The firstbolt flange 160 is just large enough for one bolt hole to extendtherethrough, and the first bolt flange 160 is contained on just thethird side wall 156, though it is conceived that the first bolt flange160 can extend onto the first side wall 142 and/or the second side wall146. Minimizing the first bolt flange 160 reduces size, weight, andmaterial. Similarly, the second bolt flange 162 is just large enough forone bolt hole to extend therethrough, and the second bolt flange 162 iscontained on just the fourth side wall 158, though it is conceived thatthe second bolt flange 162 can extend onto the first side wall 142and/or the second side wall 146. Minimizing the second bolt flange 162reduces size, weight, and material.

Corresponding bolt flanges 164, 166 are positioned on the valve cover150, and bolts 164 can extend through the pair of bolt flanges 160, 164and through the pair of bolt flanges 162, 166 to secure the valve cover150 to the valve body 102. Facilitated by the reduced size and weight ofthe wedge gate valve 100 over conventional wedge gate valves, as well asthe clamping force of the top cover 150 on the valve body 102, no morethan two bolts are necessary to secure the top cover 150 to the valvebody 102.

A valve cover cap 170 is attached to the valve cover 150. The valvecover 150 has a first pair of pin flanges 172 and a second pair of pinflanges 174. The valve cover cap 170 can have a body portion 171 (e.g.,cylindrical), from which a first pin flange 176 and a second pin flange178 extend radially outward. Each pin flange 176, 178 can have a pinhole with an axis oriented perpendicular to a center axis of the valvecover cap 170 (e.g., axis 124 in FIG. 3). A first pin 180 can beinserted through the first pair of pin flanges 172 of the valve cover150 and the first pin flange 176 of the valve cover cap 170. A secondpin 181 can be inserted through the second pair of pin flanges 174 ofthe valve cover 150 and the second pin flange 178 of the valve cover cap170.

A seal element or gasket 182 can seal between the valve cover 150 andthe valve cover cap 170. The valve cover 150 has a first sealing surface183 sized and shaped to mate with the gasket 182. The valve cover 150also has a second sealing surface 184 rising from the first sealingsurface 183. The second sealing surface 184 is configured to extendthrough the gasket 182 and contact or seal against a radially inwardlyfacing surface 185 of the gasket 182 surface.

The valve cover cap 170 has a hollow interior, with a sealing surface186 also sized and shaped to mate with the gasket 182, such that thevalve cover cap 170 can be fitted over and around the second sealingsurface 184 onto the gasket 182, and pushed downward to compress thegasket 182 between the first sealing surface 183 of the valve cover 150and the sealing surface 186 of the valve cover cap 170. Then the firstpin 180 and the second pin 181 can be assembled to secure the valvecover cap 170 to the valve cover 150. Assembly and disassembly with thepins requires less effort than assembly and disassembly with theconventional bolts.

FIG. 5 shows a perspective view of a gate valve body 200, according toan embodiment, and a perspective view of the gate 120 fully assembledand exploded. FIG. 6 shows a front view of the gate valve body 200, withthe gate 120 in the gate valve body 200. FIGS. 7, 8, and 9 show crosssectional side views of the gate valve body and gate 120 along sectionlines C, B, and A, respectively. Referring to FIGS. 5-9, the gate valvebody 200 is identical to the gate valve body 102, with the except thatthe gate valve body 200 omits the first and second flanges 110, 112 ofthe gate valve body 102. All other features of the gate valve body 200are referenced and labeled the same as the gate valve body 102.

The gate 120 includes a first body portion 202 and a second body portion204, that are configured to connect and be held together or wedgedapart, pivoting apart like a clamshell. The first body portion 202 andthe second body portion 204 can each have a shape to match and seal theflow passage 104, which is generally like a disc with the center guide136. The first body portion 202 has an exterior surface 203, on thesecond side 144 of the gate 120, facing away from the second bodyportion 204. The second body portion 204 has an exterior surface 205, onthe first side 138 of the gate 120, facing away from the first bodyportion 202. The first body portion 202 and the second body portion 204are configured to be pivoted to a position wherein the exterior surface203 of the first body portion 202 and the exterior surface 205 of thesecond body portion 204 are substantially parallel. In this position, amaximum width W2 of the gate 120, excluding the center guide 136, issubstantially uniform across the entire diameter D1 of the disc. Themaximum width W2 is smaller than that of conventional gates by at leastthe extra width of the wedge portion in conventional gates. Accordingly,the gate channel 122 is that much smaller as well, because the width W1of the gate channel 122 can be minimally larger than the width W1, andcan be constant across a length extending from an intersection of theflow passage 104 and the gate channel 122 away from the flow passage104. In some embodiments, the width W1 can taper over the length to theintersection of the flow passage 104 and the gate channel 122 at anangle less than five degrees, less than four degrees, less than threedegrees, less than two degrees, or less than one degree. The smallerresulting maximum value for the width W1 translates to a significantreduction in material and weight of the gate valve 102.

A first pivot connection element 210 and a second pivot connectionelement 211 are on an inside surface 212 of the first body portion 202and on an inside surface 213 of the second body portion 204 near,adjacent, or at a perimeter of the disc, with the center guide 136between the first pivot connection element 210 and the second pivotconnection element 211. To facilitate making the first body portion 202and the second body portion 204 identical, one of first and second pivotconnection elements 210, 211 can be “male” and the other can be“female”. In particular, one of the first and second pivot connectionelements 210, 211 on the first body portion 202 can have a protrudingportion 214 that is angled or arched to fit in a receptacle 216 of theother on the second body portion 204, and to facilitate pivoting of thefirst body portion 202 with respect to the second body portion 204.Alternatively, the first and second pivot connection elements 210, 211of the first body portion 202 can be identical—either male or female,and then matching pivot connection elements on the second body portion204 can be identical—the other of male or female. Two pivot connectionelements are depicted on each body portion, 202, 204, and symmetricallyplaced on either side of the center guide 136, to facilitate stablepivoting. More or less pivot connection elements 210, 211 can beincluded, though.

The pivoting is facilitated by a first wedging element 220 and a secondwedging element 222. Each of the first body portion 202 and the secondbody portion 204 include the first wedging element 220 and the secondwedging element 222. The first wedging element 220 and the secondwedging element 222 extend from the perimeter of the disc at a locationdiametrically opposed to the location of the first and second pivotconnection elements 210, 211, adjacent the center guide 136, with thecenter guide 136 between the first wedging element 220 and the secondwedging element 222. The first wedging element 220 includes a firstwedging surface 230 and a hook 232. Referencing the second body portion204 as an example, the first wedging surface 230 and the hook 232together define a slot 234 oriented at an angle A1 between 0 and 90degrees toward the first body portion 202 from a plane 236 perpendicularto a plane 238 of the disc shape of the second body portion 204. Thefirst wedging surface 230 is approximately equal to the angle A1. Here,“approximately” can mean plus or minus anywhere from 10 degrees, to plusor minus 0.1 degrees. The angle A1 can also be between 15 and 75degrees, 30 and 60 degrees, or another range, such that pressure againstthe first wedging surface 230 parallel to the center axis 124 of thegate channel 122 forces the second body portion 204 to pivot apart fromthe first body portion 202. Axial pressure against the hook 232 fromwithin the slot 234 draws the second body portion 204 pivotably towardthe first body portion 202.

The second wedging element 222 includes a second wedging surface 240.Still referencing the second body portion 204 as an example, the secondwedging surface faces at an angle A2 between 0 and 90 degrees fromradially outward toward the plane 238 of the disc shape of the secondbody portion 204. The angle A2 can also be between 15 and 75 degrees, 30and 60 degrees, or another range, such that pressure against the secondwedging surface 230 in a direction parallel to the center axis 124 ofthe gate channel 122 forces the second body portion 204 to pivot apartfrom the first body portion 202.

To facilitate symmetrical forces driving movement between the open andclosed positions of the gate valve 100, and to facilitate making thefirst and second body portions 202, 204 identical, each of the firstbody portion 202 and the second body portion 204 can have the firstwedging element 220 and the second wedging element 222, as illustratedin the figures, though other numbers and arrangements of the first andsecond wedging elements 220, 222 are conceived.

Pressure is applied to the first wedging surface 230, the hook 232, andthe second wedging surface 240 by rotating the stem 130, which asdiscussed above, engages the threaded portion 135 of the gate 120, suchthat the gate 120 is threaded linearly along the threaded portion 134 ofthe stem 130. The threaded portion of the gate 120 is part of a threadedcollar 242 configured to be positioned between the first and secondwedging elements 220, 222 of each of the first body portion 202 and thesecond body portion 204. The collar 242 includes two wedge pins 244,which each extend into one of the respective slots 234. The first andsecond body portions 202, 204 are biased toward each other at the firstand second wedging elements 220, 222 such that as the collar 242 ismoved along the threaded portion 134 of the stem 130 toward the centerof the first and second body portions 202, 204, if there is no otherforce on the gate, then the first body portion 202 and the second bodyportion 204 move with the collar 242. If there is another resistiveforce against movement of the first and second body portions 202, 204,though, such as occurs when the first and second body portions 202, 204are pushed into the perimeter surface 114 of the flow passage 104, thenthe collar 242 continues to move axially a distance relative to thefirst and second body portions 202, 204, and the wedge pins 244 pressagainst the first and second wedging surfaces 230, 240, therebypivotably wedging apart the first and second body portions 202, 204.FIGS. 6-9 show the gate 120 in the closed position, with the first bodyportion 202 and the second body portion 204 wedged apart from each otherat the first and second wedging elements 220, 222.

Moving the collar 242 in the opposite direction, toward the valve cover170, presses the wedge pins 244 against the hook 232, which combinedwith the bias of the first and second body portions 202, 204 toward eachother, draws the first and second body portions 202, 204 toward eachother if there is room for the first and second body portions 202, 204to move in this fashion, after which, the first and second body portions202, 204 move in synchronization with the collar 242.

The assembled gate 120 can have an elastic rubber jacket or coating 250(shown in FIGS. 3 and 5), which can provide the bias of the first andsecond body portions 202, 204 toward each other. Further, the rubberjacket or coating 250 can facilitate sealing between surfaces of thegate 120 and surfaces of valve body 102.

FIGS. 10-12 show the formation of the seal between the gate 120 and thevalve body 102 as the gate 120 moves into the closed position and thefirst and second body portions 202, 204 are wedged apart. FIG. 10 showsa cut away, partially transparent perspective view of the wedge gatevalve 100 of FIG. 3. As the stem 130 is rotated and the collar 242pushes the first and second body portions 202, 204 toward the perimetersurface 114 of the flow passage 104, a radially facing surface 260 ofthe first and second body portions 202, 204 contacts the perimetersurface 114.

At this position, as the stem 130 is further rotated, the first andsecond body portions 202, 204 can move no further along the center axis124 of the stem 130, and the wedge pins 244 wedge apart the first andsecond body portions 202, 204. FIG. 11 shows a cut away, partiallytransparent, perspective view of the wedge gate valve 100 of FIG. 3,with the first and second body portions 202, 204 wedged apart. Thediameter D1 of the gate 120 can be larger than a diameter D2 (see FIG.3) of the flow passage 104, such that in this closed position, theexterior surfaces 203, 205 of the first and second body portions 202,204 seal against the second and first side walls 146, 142 of the gatechannel 122. Referring to FIG. 10 and FIG. 11, a semi-annular slot 262extends from the gate channel 122 through the perimeter surface 114beyond a plane 254 perpendicular to the center axis 124 of the gatechannel 122, the plane 254 parallel to and intersecting with the centeraxis 126 of the flow passage 104. In other words, an internal span S ofthe gate channel 122 is greater than the diameter D2 of the flow passage104, as measured through the diameter D2, and the gate channel 122encircles a majority of a circumference of the flow passage 104, therebydefining, at least in part, the semi-annular slot 262.

The gate 120 fits within the semi-annular slot 262, and the diameter D1of the gate is large enough such that the gate 120 extends into thesemi-annular slot 262. The semi-annular slot 262 has surfaces 264 thatface generally in a direction parallel to the center axis 126 of theflow passage 104. When the first and second body portions 202, 204 arewedged apart, the exterior surfaces 203, 205 contact and seal againstthese axially-facing surfaces 264.

FIG. 12 shows a cut away perspective view of the wedge gate valve 100 ofFIG. 3, with the gate 120 in a closed position. The semi-annular slot262 tapers out relatively gradually into the perimeter surface 114. Theinteraction between the semi-annular slot 262, its gradual taper, andthe location of the taper with the gate 120 help define a sealtransition 270 between the radially facing surface 260 of the gate 120and the axially facing exterior surface 205 of the gate 120. Thetransition 270 is more gradual, with more overlap, than in conventionalgate valves. The transition 270 is also closer to a location on theperimeter of the gate 120 diametrically opposite the collar 242 than inconventional wedge gate valves, such that the transition 270 experiencesmore axial force into the perimeter surface 114 of the flow passage 104.With the greater axial force, the radially facing surface 260 has agreater likelihood of sealing at the transition 270, in addition to thesealing of the exterior surface 205 at the transition 270. As a result,the valve body 102 including the semi-annular slot 262, and the gate 120can be manufactured with less precision and greater tolerance, and henceless cost, to achieve a seal with integrity equal to or better thanconventional wedge gate valves.

Further, the fit of the gate 120 within the semi-annular slot 262 canassist guidance of the gate 120 movement between the open and closedposition.

Accordingly, it is to be understood that the embodiments of theinvention herein described are merely illustrative of the application ofthe principles of the invention. Reference herein to details of theillustrated embodiments is not intended to limit the scope of theclaims, which themselves recite those features regarded as essential tothe invention.

What is claimed is:
 1. A gate valve comprising: a valve body including afirst opening, a second opening, a flow passage from the first openingto the second opening, and a gate channel intersecting the flow passage,the gate channel being defined in part by two side walls facing parallelto a center axis of the flow passage, at least one of the two side wallshaving a concave slot extending lengthwise along a center of the atleast one of the two side walls; and a gate including a firstdisc-shaped side and a second disc-shaped side, the first disc-shapedside including a first center guide and a first diameter, the firstcenter guide being a convex ridge extending across the first diameter,the convex ridge configured to slide within the concave slot.
 2. Thegate valve of claim 1, wherein the concave slot has a uniform curvature.3. The gate valve of claim 1, wherein the flow passage has an outerdiameter and the gate channel has a span perpendicular to a center axisof the gate channel, the span containing the outer diameter of the flowpassage and being greater than the outer diameter of the flow passage asmeasured through the outer diameter of the flow passage.
 4. The gatevalve of claim 3, wherein the flow passage has a circumference, andwherein the gate channel encircles a majority of the circumference. 5.The gate valve of claim 1, wherein the second disc-shaped side includesa second center guide and a second diameter, the second center guidebeing a convex ridge extending cross the second diameter.
 6. The gatevalve of claim 1, wherein the gate channel intersects with the flowpassage to form a first semi-annular slot and a second semi-annular slotthrough a circumference of the flow passage on diametrically opposedsides of the flow passage, wherein the gate has a width from the firstdisc-shaped side to the second disc-shaped side, the width of the gatefitting within a width of the first and second semi-annular slots. 7.The gate valve of claim 6, wherein the first diameter and the seconddiameter extend from within the first semi-annular slot to within thesecond semi-annular slot.
 8. The gate valve of claim 1, wherein thefirst center guide of the first disc-shaped side fits congruentlyagainst the concave slot of the side walls of the gate channel.